WALTHAM, Mass. — Rajon Rondo sought out advice from all over the sports landscape both before and after his ACL surgery in February. Patriots receiver Wes Welker and former teammates Kendrick Perkins and Tony Allen all got calls from the Celtics point guard, who came away with a couple of impressions.

One, there is no way to tell, from one case to the next, how an individual will come back from such an injury. And two, the mental recovery will be much tougher than the physical recovery.

With a renewed perspective, Rondo used his time with reporters at Celtics media day on Monday to defend Derrick Rose, who came under fire for supposedly delaying his comeback from his own torn ACL.

“When I’m mentally ready, I’ll play,” Rondo said. “Until you go through this type of injury, [you can’t know]. A lot of people gave Derrick Rose a lot of heat about not playing or whatever the case may be, but this injury isn’t difficult. I mean, it isn’t easy, but at the same time it’s more mental when you come back. When you get around 10, 11 months, it’s about feeling confident.”

Rondo and Rose have not spoken, but they are coming from a similar place mentally, Rondo said. Neither of them left the ground for months, a drastic change for two guys who have spent their lives playing a game in which jumping is almost as common as breathing.

“We have to feel confident, especially the type of players as point guards we are,” Rondo said. “Our legs are pretty much everything. With our speed, he’s very athletic, and you need that mental aspect to go out there and jump and come down without thinking about your leg injury. The last time we jumped, me and Derrick, we came down and tore an ACL, so it’s just being mentally ready. When I get there, I’ll play.”

Rondo has yet to be cleared for contact activities, but he has gotten back on the court to work on his ballhandling and shooting in addition to light running. He did not dispute or confirm the December return date that Celtics president of basketball operations Danny Ainge has speculated could be Rondo’s target date.